problems with yahoomail, diff browsers



I have serious (recent) problems with yahoo mail.
I can't send e-mails, and in many cases i can't open them either
(sometimes i can, but one time out of ten, after trying for a very
long time). Furthermore, i cannot go directly anymore to yahoo mail, i have to use a google link..
I received one e-mail today, i can't say if more were blocked coming
from other e-mail addresses. Maybe not.

In these 4 cases the problems occur:

1. Classic mail on Safari 1.3.2 on Mac OSX 10.3.9
2. Classic mail on Firefox on Mac OSX 10.3.9
3. Classic Mail on Firefox 3.5.9 on Mac OSX 10.4.11
4. All New Yahoo mail on Firefox 3.5.9 on Mac OSX 10.4.11

One might initially think it's because of the older versions of the
browsers (1. and 2., worked well until a few days ago), but 3. and 4.
tell me that the problem might be different, since Firefox 3.5.9 is a
very recent browser.

What could be the problem? Think i have recent versions of Java on the two drives, and everything's ok with my disk permissions.

Kind regards,